ALLOWED_IPS validation too strict

[snophey]

The validation function is designed such that the examples given in the README.md do not pass validation:

validate_allowed_ips() {
    local ips="$1"
    # Validate AllowUsers entries and IP addresses
    if ! echo "$ips" | grep -E '^(AllowUsers|from) [a-zA-Z0-9@., ]+$'; then
        echo "Invalid ALLOWED_IPS format"
        exit 1
    fi
}

This example scenario from the readme would not pass validation by the above function:

ALLOWED_IPS="AllowUsers *@192.168.1.0/24 *@172.16.0.1 *@10.0.*.1"